Vintage Transistor Radio Gets Internet Transplant

The invention of the transistor revolutionized radio, allowing receivers to be made far more compact and portable than ever before. In the middle of the 20th century, the devices exploded in popularity, and pocket transistor radios took the market by storm. [MisterM] had fond memories of such times, and when he found a 1970s Flirt radio at a car boot sale, it led to a cute little build.

The radio was stripped of its original hardware, with [MisterM] preferring internet radio to the terrestrial variety. In its place, a Raspberry Pi Zero was installed. This was fitted with a cavalcade of off-the-shelf modules to make it fit for pumping out the tunes. A Speaker PHAT was used for audio, while an Adafruit Micro Lipo board handled battery charging and a Pimoroni Lipo Shim served as the power supply. All this was bundled up inside the original casing.

The radio’s controls are a neat hack. The original volume and tuning dials were removed, sliced up, and glued onto two lever microswitches. This allows them to act as buttons instead. A new power switch was installed behind the original, and the Speaker PHAT’s LEDs were placed behind the tuning dial to act as a rudimentary display.

It’s a tidy build that repurposes an attractive vintage artefact into a device of the internet age, while remaining externally the same. [MisterM] has form in this space, with his vintage radio console build and video doorbell being particular highlights. Video after the break.

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An Algorithm For De-Biasing AI Systems

A fundamental truth about AI systems is that training the system with biased data creates biased results. This can be especially dangerous when the systems are being used to predict crime or select sentences for criminals, since they can hinge on unrelated traits such as race or gender to make determinations.

A group of researchers from the Massachusetts Institute of Technology (MIT) CSAIL is working on a solution to “de-bias” data by resampling it to be more balanced. The paper published by PhD students [Alexander Amini] and [Ava Soleimany] describes an algorithm that can learn a specific task – such as facial recognition – as well as the structure of the training data, which allows it to identify and minimize any hidden biases.

Testing showed that the algorithm minimized “categorical bias” by over 60% compared against other widely cited facial detection models, all while maintaining the same precision of detection. This figure was maintained when the team evaluated a facial-image dataset from the Algorithmic Justice League, a spin-off group from the MIT Media Lab.

The team says that their algorithm would be particularly relevant for large datasets that can’t easily be vetted by a human, and can potentially rectify algorithms used in security, law enforcement, and other domains beyond facial detection.

Build Yourself A Set Of Glowing Wings

Humans didn’t come with wings from the factory, and most efforts to fit them after the fact have been at least as far as flight is concerned, largely fruitless. That doesn’t mean you can’t cut a devastatingly sharp aesthetic though, and [Natalina’s] fiber optic wings are a great way to do just that. 

The wings are a leathercraft project, consisting of a harness worn around the torso. This serves as the mounting point for the fiber optics, as well as the RGB Critter flashlight used to drive the lightshow. Leather parts are lasercut to the right shape, making it easy to create the delicate feather shapes in the design. The pieces are then dyed appropriately and sewn together into the final shape. Bundles of optical fibers are then wound through the harness, sprouting from either shoulder of the wearer. EVA foam is used to help create the right shape for the wings, allowing the different layers to remain separated to create more visual depth.

It’s a build that looks absolutely striking at night, and unlike some other wing-based cosplays, doesn’t have as many drawbacks as far as crowds and transportation. It would make a killer look if you’re going as a Hacker Angel for Halloween this.

Makers certainly know how to craft some cutting-edge wearables. Got your own sweet build? Throw it at the tips line!

An Optocoupler Doorbell Notifier

Over the years we’ve seen several attempts at adding Internet connectivity to the lowly wired doorbell. Generally, these projects aim to piggyback on the existing wiring, bells, and buttons rather than replace them entirely. Which invariably means at some point the AC wiring is going to need to interface with a DC microcontroller. This is often where things get interesting, as it seems everyone has a different idea on how best to bridge these two systems.

That’s the point where [Ben Brooks] found himself not so long ago. While researching the best way to tap into the 20 VAC pumping through his doorbells, he found a forum post where somebody was experimenting with optocouplers. As is unfortunately so often the case, the forum thread never really had a conclusion, and it wasn’t clear if the original poster ever figured it out.

DIY optocouplers wrapped in electrical tape

[Ben] liked the idea though, so he thought he would give it a shot. But before investing in real optocouplers, he created his own DIY versions to use as a proof of concept. He put a standard LED and photoresistor together with a bit of black tape, and connected the LED to the doorbell line with a resistor. Running the LED on 60 Hz AC meant it was flickering rapidly, but for the purposes of detecting if there was voltage on the line, it worked perfectly.

Wanting something slightly more professional for the final product, [Ben] eventually evolved his proof of concept to include a pair of 4N35s, a custom PCB, and a 3D printed enclosure. Powered by a Particle Xenon, the device uses IFTTT to fire off smartphone notifications and blink the lights in the house whenever somebody pushes the bell.

If you’re still wondering why it’s so tricky to connect a microcontroller up to your door bell, a quick look at some of the similar projects we’ve covered should give you a pretty good idea of how annoying these systems can be to modernize.

A DIY Retrocomputer Programmed In Pure Rust

Can you generate VGA and handle a PS/2 keyboard with a Cortex-M4 in Rust? That’s precisely what [theJPster] wanted to find out with Monotron, a 1980s style home computer programmed in pure Rust.

In order to run embedded Rust without a working operating system, some tools are necessary: an LLVM back-end for generating machine code, a target file for specifying memory sizes and other configs, and a pre-compiled libcore as a substitute for a compiler when running an operating system. Rust takes the place of C running on top of the board support package (BSP) and hardware abstraction layer (HAL), and peripheral access crates (PACs) that specify the hardware and allow the code to be portable across different chips.

The implementation maps generates 800 x 600 VGA video signal at 60 Hz, displays text on a 48 character by 36 line display, displays color graphics using color lookup (stored in flash memory), and runs applications that take less than 24 KiB for all data. Monotron also generates 8-bit audio with PWM and sports a synthesizer uses a three-channel wavetable allowing it to make sounds with square waves, sine waves, sawtooth waves, and create white noise.

So far, the Monotron has been able to work with an Atari joystick, a PS/2 keyboard, and outputs to VGA, MIDI, SD card, and audio. Next up for the Monotron – writing a programming language (tentatively named Monotronian), adding support for Sega Megadrive pads, displaying sprites, and many more excitement developments.

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How To Make An Electric Scooter Chain Sprocket With Nothing But Hand Tools

Sometimes, mechanical parts can be supremely expensive, or totally unavailable. In those cases, there’s just one option — make it yourself. It was this very situation in which I found myself. My electric scooter had been ever so slightly bested by a faster competitor, and I needed redemption. A gearing change would do the trick, but alas, the chain sprocket I needed simply did not exist from the usual online classifieds.

Thus, I grabbed the only tools I had, busied myself with my task. This is a build that should be replicable by anyone comfortable using a printer, power drill, and rotary tool. Let’s get to work!

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Open Hardware Month Hack Chat

Join us on Wednesday, October 23 at noon Pacific for the Open Hardware Month Hack Chat with Michael Weinberg!

It seems like everything and everyone has a special day set aside on the calendar. You know the drill – a headline declaring it National Grilled Cheese Day (sorry, you missed it – April 12) or National Bundt Pan Day (not even kidding, November 15). It seems only fair with all these silly recognition days floating around that we in the hacking community should have a day of our own, too, or even a whole month. That’s why the Open Source Hardware Association declared the entire month of October to be Open Hardware Month.

Open hardware is all about accessible, collaborative processes that let everyone see and understand the hardware they’re using. The technological underpinnings of our lives are increasingly hidden from us, locked away as corporate secrets. Open hardware tries to turn that on its head and open up devices to everyone, giving them the freedom to not only use their devices but to truly understand what’s happening in them, and perhaps repair, extend, and even modify them to do something new and useful. Celebrating that and getting the message out to the general public is certainly something worth doing.

Michael Weinberg is a board member at OSHWA, and he’ll be joining the Hack Chat on October 23 (National Boston Cream Pie Day) to discuss Open Hardware Month and open-source hardware in general. We’ll learn about some of the events planned for Open Hardware Month, how open hardware is perceived beyond the hacker community, and what’s on tap for the 10th anniversary Open Hardware Summit in 2020.

join-hack-chatOur Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, October 23 at 12:00 PM Pacific time. If time zones have got you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.